<ul style="padding:0 5px;background: rgb(228, 196, 215)">
  <li routerLink="twoChild1" routerLinkActive="activeChild">twoChild1</li>
  <li routerLink="twoChild3" routerLinkActive="activeChild">twoChild3</li>
  <li routerLink="twoChild2" routerLinkActive="activeChild">twoChild2</li>
</ul>
<router-outlet></router-outlet>